【作者】 向道朴；

【导师】 何建国；

【作者基本信息】 国防科学技术大学 ， 电子科学与技术， 2010， 博士

【摘要】 微动目标电磁散射回波中包含精细的微多普勒特征信息,这些特征信息与目标物性参数,如目标质量分布特征、惯性比特征和发动机特征等之间具有特定的对应关系,被视为目标独一无二的特性,在目标识别方面具有独到的优势。研究微动目标电磁散射回波数值模拟技术和微动特征提取技术,在工程上具有重要应用价值。针对微动目标雷达回波数值模拟问题,本文提出应用准静态技术结合多层快速多极子算法,计算实际雷达目标因微动激励的微多普勒雷达回波;针对微动特征提取问题,本文提出了一类改进的高分辨时频分析算法,并应用该算法对计算得到的微多普勒雷达回波进行了分析,从中提取出了目标微动的细节信息。论文首先对国内外运动目标雷达回波模拟的研究现状、论文的研究背景、论文的主要工作及章节安排进行了阐述;接着研究了准静态技术的基本原理以及应用准静态技术结合多层快速多极子算法计算微动目标激励的多普勒雷达回波的方法和具体步骤;然后研究了微动目标低分辨雷达特征提取技术,对基于高分辨时频分布的两种微多普勒雷达回波瞬时频率的估计算法及性能进行了理论分析与仿真计算,并对实际中特别重要的目标微动分辨及微动参数估计问题进行了专门研究。作为理论研究的应用,论文研究了直升机目标和弹道导弹目标分辨问题。首先分析了直升机目标的回波特性,计算了直升机模型激励的微多普勒雷达回波,并基于高分辨时频像提取出了直升机的运动信息;然后应用独立成分分析技术(ICA)研究了中段弹道导弹弹头与诱饵分辨问题,由于低分辨雷达不具有距离分辨力,因此只有依靠弹头与诱饵运动形式的不同来实现目标分辨,这就要求能准确的从弹头与诱饵群目标多普勒回波中估计出各自的瞬时频率。论文给出了独立成分分析的基本原理及算法实现的细节,并应用独立成分分析技术成功的从弹道导弹弹头与诱饵目标群中分辨出了具有威胁的弹头。最后,对论文的研究工作和所取得的成果进行了总结,指出了需要进一步研究和解决的问题。更多还原

【Abstract】 The electromagnetic scattering echo of a micro-motion target contains precision micro-Doppler signature information, these information are corresponding with the physical parameters of the target, such as mass distribution, inertial ratio and engine characteristic. These characteristics are always seen as the unique characteristic of the target and playing very important role in the area of target identification. To investigate the simulation of micro-Doppler echo and the signature extraction from targets with micro-motions has significant value in engineering. For micro-Doppler echo simulation, we propose to use the quasi-static method coherent with multilevel fast multipole method to compute the micro-Doppler echo induced by micro-motion body. For micro-dynamic signature extraction, we propose to use an improved high resolution time-frequency analysis algorithm. We use this algorithm to analyze the echo signals that we got from the computing and we got the detail information of the micro-motion body based on the analysis.In the introduction, there are brief reviews and comments of the research background as well as present situation of the subject, and then the main contributions of the dissertation are introduced, in which the frame of the dissertation are particularly pointed out. Coherently, the principle of the quasi-static method is introduced and the procedure of using the multilevel fast multipole method to compute the micro-dynamic echo is presented. After that, we investigate the micro-Doppler signature extraction technology, we presenting the capability of the two instantaneous frequency estimation methods based on the high resolution time-frequency profile, and the micro-motion classification and micro-motion parameter estimation are particularly pointed out.There are specific application researchs of our theory. Firstly, the echo’s signature of helicopter is analyzed and the micro-Doppler radar echo induced by real-estate helicopter model’s rotating blades is calculated, then the motion signature of helicopter is extracted based on high resolution time-frequency profile. Secondly, we use Independent Component Analysis method (ICA) to investigate the warhead and baits separation in mid- ballistic trajectory. As low resolution radar has no range resolution, there is one way for us to separate the warhead and baits via the differenct motion feature of them, so we need to extract the instantaneous frequency of the warhead and baits precisely. The principal theory and the algorithm of ICA are introduced conceretely and we use ICA method to separate the warhead and baits successfully.The dissertation is concluded with current trends and future outlook in the subject. In particular, some significant and valuable problems are pointed out for further research.更多还原